Improvement in extension-ladders



M. N. LOVE-LL. Extension Ladders.

Patented Aug. 4,1874.

Attorneys y me GRAPHIC mPHm-o-wmass. 4| man Pua UNITED STATES PATENTOFFICE.

MELVIN N. LOVELL, OF ERIE, PENNSYLVANIA.

IMPROVEMENT IN EXTENSION-LADDERS.

Specification forming part of Letters Patent No. 153,716, dated August4, 1874; application riled J nne 18, 1874.

To all whom it may concern:

Be it known that I, MELVIN N. LovELL, of Erie, in the county of Erie andin the State of Pennsylvania, have invented certain new and usefulImprovements in Extension-Ladder; and do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings and to the letters of referencemarked thereon, making a part of this specification.

The nature of my invention consists in the peculiar construction andarrangement of a device to be used with extension-ladders, for lockingand holding them in position, as will be hereinafter set forth.

In the annexed drawings, Figurel is a perspective of two ladderspartially extended, and Fig. 2 is a perspective view of the lockin gdevice taken from the inner face.

In the figures, A and B represent two ladders, one made a littlenarrower than the other, so that the narrow one can lie and slide uponthe rounds of the wider one. C represents a rope which has both of itsends made fast to the lowest round of one ladder after having passedover or around the lowest round of the other ladder, and then through apulley-block on the highest round of same. The locking device consistsof a hooked arm, E, a bell-crank, F, and the metal box Gr. One end ofthe arm E is pivoted, as seen at as in the box P. Two of these boxes areused with the inner ladder, and secured to it, as seen, near its lowerend. The hook 1' upon the arm is intended to catch upon the rounds ofthe larger ladder, and thus hold the two at any desired position. Thepoint e of the bellcrank F reaches a little beyond the point of the hooki, and the other end of said crank being heavier the two points are keptin contact, except when the crank is moved by coming in contact with therounds. Upon theinner side of the crank F is formed a rib or flange, a,so that when the point e is struck and moved backward by the round theflange will come in contact with the arm E and allow it to moveonlyso-far. This flange prevents any displacement of the crank, and assuresits proper working. The arm E plays upon its pivot sufficiently to riseover and drop upon the rounds in its operation. When the the ladder B isdropped, the point e resting against the point of the hook i, preventssaid hook from catching the round, and the arm E passes over the roundswith ease.

I do not claim the vertically pivoted and hooked lever, having a pawl orlever pivoted thereto, without the employment of the flange or rib uponthe inner face of the bell-crank lever F.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is-

The flange a on the weighted bell-crank lever F, in combination with thearm E and box G, as constructed, all substantially as set forth.

In testimony that I claim the foregoing I have hereunto set my hand this20th day of May, 1874.

MELVIN N. LOVELL.

Witnesses J NO. K. HALLOGK, ROBERT H. PORTER.

